Every time someone interviews an astronaut, or an astronomer whose team has just discovered some new extra-solar planets, they have to answer the question about whether they think there’s intelligent life out among the stars.
Usually, they say that given the vast scale of the galaxy, with its billions upon billions of stars, surely somewhere out there are other intelligent beings, or at least ones that can fake it, like we do.
There’s even a famous math problem/hypothesis about this, called the Drake Equation.
Basically, the equation asks you to plug in the number of stars in the galaxy, the number of those stars that might have habitable planets, the number of planets where life evolves, the number on which intelligent life evolves, and so on.
The fun part is that most of those are unknown. We have only just started to get a handle on how many planets might exist beyond our solar system in the last 20 years! We have no idea whatsoever about how many of them might have liquid water, or be capable of supporting life.
But the Drake Equation is asking the right questions, aimed in the wrong direction.
Okay, we’re an intelligent species, we’ve got radio telescopes and space probes.
But look at the entire time our planet has supported life.
What tiny, tiny slice of that time includes humans? And what even more minuscule fraction includes humans who had figured out how to make anything more complex with a stone axe?
Did you know that there’s an era in Earth’s deep history that geologists call the Boring Billion? Almost nothing of note happened. Even the continents just sat there, listlessly.
But there was life on Earth then! It’s been around for about 3.7 billion years!
Admittedly, for most of that time, most of life was different kinds of slime.
The earliest evidence we have for multi-cellular organisms is about 2.1 billion years old. The fossils of those creatures look sort of like gooey flying saucers, about 15 centimetres across. They likely would have resembled some sort of jellyfish, bobbing around in the oceans.
So the question for the Drake Equation is, how long do technological civilizations last?
Let’s plug in some very optimistic numbers to the Drake Equation. Lots of planets! Life abundant and common!
But, does that help us find any other intelligent life?
Not if we just missed them, by 10 or 50 or 200 million years or so.
We don’t know what sparked life on Earth to jump from single-celled mats of goo to multi-cellular animals, from there to complex forms with actual brains, from there to tool-using creatures. Maybe each step was incredibly improbable!
But even if it wasn’t, even if many, many planets birth a species as intelligent as we are, well, we probably missed out already.
The absence of signals from the stars doesn’t necessarily mean life or intelligence is uncommon.
It means it doesn’t last that long.
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